Human DNA, the Ultimate Spot for Secret Messages (Are Some There Now?)

In Douglas Adams’s science fiction classic, “The Hitchhiker’s Guide to the Galaxy,” there is a character by the name of Slartibartfast, who designed the fjords of Norway and left his signature in a glacier.

I was reminded of Slartibartfast recently as I was trying to grasp the implications of the feat of a team of Japanese geneticists who announced that they had taught relativity to a bacterium, sort of.

Using the same code that computer keyboards use, the Japanese group, led by Masaru Tomita of Keio University, wrote four copies of Albert Einstein’s famous formula, E=mc2, along with “1905,” the date that the young Einstein derived it, into the bacterium’s genome, the 4.2-million-long string of A’s, G’s, T’s and C’s that determine everything the little bug is and everything it’s ever going to be.

The point was not to celebrate Einstein. The feat, they said in a paper published in the journal Biotechnology Progress, was a demonstration of DNA as the ultimate information storage material, able to withstand floods, terrorism, time and the changing fashions in technology, not to mention the ability to be imprinted with little unobtrusive trademark labels — little “Made by Monsanto” tags, say.

In so doing they have accomplished at least a part of the dream that Jaron Lanier, a computer scientist and musician, and David Sulzer, a biologist at Columbia, enunciated in 1999. To create the ultimate time capsule as part of the millennium festivities at this newspaper, they proposed to encode a year’s worth of the New York Times magazine into the junk DNA of a cockroach. “The archival cockroach will be a robust repository,” Mr. Lanier wrote, “able to survive almost all conceivable scenarios.”

If cockroaches can be archives, why not us? The human genome, for example, consists of some 2.9 billion of those letters — the equivalent of about 750 megabytes of data — but only about 3 percent of it goes into composing the 22,000 or so genes that make us what we are.

The remaining 97 percent, so-called junk DNA, looks like gibberish. It’s the dark matter of inner space. We don’t know what it is saying to or about us, but within that sea of megabytes there is plenty of room for the imagination to roam, for trademark labels and much more. The King James Bible, to pick one obvious example, only amounts to about five megabytes.

Inevitably, if you are me, you begin to wonder if there is already something written in the warm wet archive, whether or not some Slartibartfast has already been here and we ourselves are walking around with little trademark tags or more wriggling and squiggling and folded inside us. Gill Bejerano, a geneticist at the University of California, Santa Cruz, who mentioned Slartibartfast to me, pointed out that the problem with raising this question is that people who look will see messages in the genome even if they aren’t there — the way people have claimed in recent years to have found secret codes in the Bible.

Nevertheless, no less a personage than Francis Crick, the co-discoverer of the double helix, writing with the chemist Leslie Orgel, now at the Salk Institute in San Diego, suggested in 1973 that the primitive Earth was infected with DNA broadcast through space by an alien species.

As a result, it has been suggested that the search for extraterrestrial intelligence, or SETI, should look inward as well as outward. In an article in New Scientist, Paul Davies, a cosmologist at Arizona State University, wrote, “So might ET have inserted a message into the genomes of terrestrial organism, perhaps by delivering carefully crafted viruses in tiny pace probes to infect host cell with message-laden DNA?”

I should say right now that I am not talking about theology or the near theology known as intelligent design. The ability to stick a message in a cockroach does not make us the designers or creators of the cockroach — only evolution could be so kind or clever.

But I’m a sucker for secret messages. Once, long ago, I stayed up all night with my friends playing the Beatles’ “White Album” backward hoping to hear the words “Turn me on dead man,” referring to the rumored death of Paul McCartney. I’m ready to find Slartibartfast’s signature and rediscover my cosmic heritage.

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The sad truth is, as others will tell you, this is a bit like writing love letters in the sand. “I don’t buy it,” said Seth Shostak, an astronomer at the SETI Institute in Mountain View, Calif., pointing out that DNA is famously mutable. “Just ask Chuck Darwin,” he added in an e-mail message.

It is the relentless shifting and mutating, the probing and testing of every possibility on the part of DNA, after all, that generates the raw material for evolution to act on and ensures the success of life on Earth (and perhaps beyond). Dr. Davies said that he had been encouraged by the discovery a few years ago that some sections of junk DNA seem to be markedly resistant to change, and have remained identical in humans, rats, mice, chickens and dogs for at least 300 million years.

But Dr. Bejerano, one of the discoverers of these “ultraconserved” strings of the genome, said that many of them had turned out to be playing important command and control functions.

“Why they need to be so conserved remains a mystery,” he said, noting that even regular genes that do something undergo more change over time. Most junk bits of DNA that neither help nor annoy an organism mutate even more rapidly.

The Japanese team proposed to sidestep the mutation problem by inserting redundant copies of their message into the genome. By comparing the readouts, they said, they would be able to recover Einstein’s formula even when up to 15 percent of the original letters in the string had changed, or mutated. “This is the major point of our work,” Nozomu Yachie said in an e-mail message. At the rate of one mutation per generation, Dr. Yachie estimated it could take at least millions of years for the bacteria’s genome to change by 15 percent — a huge change. Only 1 percent separates us from chimps. But other experts say that a stretch of DNA that is at best useless, and perhaps annoying to the little bug could disappear much more rapidly.

Calling the idea of storing information in living DNA “a nifty idea,” Dr. Bejerano said: “The bottom line is if you want something to perpetuate forever, you can’t just come in and type what you want. It would get washed away.”

That dream, he said, “is hopeless with our current knowledge.”

If we want to leave a message that would last for eons, it seems, we have to be clever enough to make sure that the message would remain beneficial to its host pretty much forever.

The challenge for an erstwhile interstellar Johnny Appleseed is to make the message part of the basic nature of its host.

If that ever turns out to be us, if we find that we are the medium, to paraphrase the late Marshall McLuhan, then, in some sense, we are also the message. Never mind who or what are the intended readers.

But if we find, say, the digits of the number pi encoded in a cockroach, I want to have a talk with old Mr. Startibartfast.

Correction: June 28, 2007

An essay in Science Times on Tuesday about the ability to encode information in a genome referred incorrectly to the number of bases, or letters, in the genetic code of a bacterium in which researchers wrote the E=mc2 formula. The bacterium’s genome has about 4.2 million bases, not 400 million.

A version of this article appears in print on , on Page F4 of the New York edition with the headline: Human DNA, the Ultimate Spot for Secret Messages (Are Some There Now?). Order Reprints|Today's Paper|Subscribe